1. Field
Example embodiments generally relate to fuel structures and radioisotopes produced therein in nuclear power plants.
2. Description of Related Art
Generally, nuclear power plants include a reactor core having fuel arranged therein to produce power by nuclear fission. A common design in U.S. nuclear power plants is to arrange fuel in a plurality of fuel rods bound together as a fuel assembly, or fuel assembly, placed within the reactor core. These fuel rods typically include several elements joining the fuel rods to assembly components at various axial locations throughout the assembly.
As shown in FIG. 1, a conventional fuel assembly 10 of a nuclear reactor, such as a BWR, may include an outer channel 12 surrounding an upper tie plate 14 and a lower tie plate 16. A plurality of full-length fuel rods 18 and/or part length fuel rods 19 may be arranged in a matrix within the fuel assembly 10 and pass through a plurality of spacers 20. Fuel rods 18 and 19 generally originate and terminate at upper and lower tie plates 14 and 16, continuously running the length of the fuel assembly 10, with the exception of part length rods 19, which all terminate at a lower vertical position from the full length rods 18.
As shown in FIG. 2, fuel elements 25 may be shaped in pellet-form and placed within the fuel rods 18 or 19. These fuel elements 25 may be “stacked” within the fuel rod continuously to provide fuel through the length of the fuel rod 18 or 19. The stacking of fuel elements 25 may permit expansion or other deformation of the fuel elements 25 during the operation cycle of the reactor core. Further, a gap 21 between the elements 25 and an inner wall 23 of the fuel rod 18 or 19 may accommodate gaseous fission products produced from the fuel elements 25 during operation of the reactor. Spring 24 at ends, typically at least an upper end, of the fuel element stack in the fuel rod may be present to further allow fission product accumulation and fuel element 25 deformation.